The present invention relates to an optical copying apparatus in general, and more particularly to an arrangement for supporting original documents to be copied on such apparatus.
Various constructions of copying apparatus, for instance, of the photostatic type, are already known and in widespread use. Basically, such optical copying apparatus exposes portions of the original documents to be copied to light rays, usually through a transparent plate or the like, and transfers images from the original document to copy sheets. The operation of the copying apparatus proper, regardless of its particular construction and mode of operation, is so well known as not to need any detailed discussion herein. In order to understand the present invention, all that is required is to realize that the optical copying apparatus has a support surface, provided on one or more of the components of the apparatus, and that the original documents to be copied are supported on such support surface, whether they be loose sheets, elongated strips or even three-dimensional objects such as books. All other details of the optical copying apparatus, particularly the way in which the copying apparatus operates, are quite unimportant for understanding the present invention.
There is already known, for instance, from the U.S. Pat. No. 3,597,074 an optical copying apparatus of the above-discussed type in which a transparent exposure plate is mounted in a frame, being inwardly offset from the exposed support surface of the frame. A hinge pivotally mounts a lid on the frame for displacement into and out of a closed position in which the lid covers at least the transparent plate. This copying apparatus further includes an arrangement which holds the lid, which is rigid, in such a position that a different portion of the original document than that which is then to be copied can be supported on the rigid lid. The holding arrangement for the lid of this copying apparatus includes support rods which can be arrested in the proper positions thereof by means of setting screws. It will be appreciated that the setting procedure is very laborious, which is especially disadvantageous in the context of present high-speed copiers. In addition thereto, the holding rods of this reference are only in line contact, rather than in surface contact, with the original document, which may be disadvantageous under some circumstances. Furthermore, a substantial amount of skill is required on the part of the operator of the copying apparatus for the operator to be able to adjust the positions of the rods in accordance with the type of the original document which is being copied by the optical copying apparatus.